I bought this for 50 dollars :
and followed their simple directions, and now we have free homephone service. The sound quality is perfect. It's really neat.
The only slightly bad thing is it doesnt have 911 service because google doesnt offer E911 service. However the box does allow you to have two VOIP service providers so if I really want it I can get a second voip service provider to handle only my 911 calls. I found some company that will only charge you the federal tax fee for that which is 1.50 per month.
Alternatively, you could just program a macro in the phone that maps 911 to the local 911 office. They wouldnt have your address info when someone called though. This method is free.